Sophie's SmartCar tore through the diplomatic quarter, weaving past embassies and consulates,finally racing out a side street and taking a right turn back onto the massive thoroughfare ofChamps-Elysées.

　　Langdon sat white-knuckled in the passenger seat, twisted backward, scanning behind them for anysigns of the police. He suddenly wished he had not decided to run. You didn't, he reminded himself.

　　Sophie had made the decision for him when she threw the GPS dot out the bathroom window.

　　Now, as they sped away from the embassy, serpentining through sparse traffic on Champs-Elysées,Langdon felt his options deteriorating. Although Sophie seemed to have lost the police, at least forthe moment, Langdon doubted their luck would hold for long.

　　Behind the wheel Sophie was fishing in her sweater pocket. She removed a small metal object andheld it out for him. "Robert, you'd better have a look at this. This is what my grandfather left mebehind Madonna of the Rocks."Feeling a shiver of anticipation, Langdon took the object and examined it. It was heavy and shapedlike a cruciform. His first instinct was that he was holding a funeral pieu—a miniature version of amemorial spike designed to be stuck into the ground at a gravesite. But then he noted the shaftprotruding from the cruciform was prismatic and triangular. The shaft was also pockmarked withhundreds of tiny hexagons that appeared to be finely tooled and scattered at random.

　　"It's a laser-cut key," Sophie told him. "Those hexagons are read by an electric eye."A key? Langdon had never seen anything like it.

　　"Look at the other side," she said, changing lanes and sailing through an intersection.

　　When Langdon turned the key, he felt his jaw drop. There, intricately embossed on the center ofthe cross, was a stylized fleur-de-lis with the initials P.S.! "Sophie," he said, "this is the seal I toldyou about! The official device of the Priory of Sion."She nodded. "As I told you, I saw the key a long time ago. He told me never to speak of it again."Langdon's eyes were still riveted on the embossed key. Its high-tech tooling and age-oldsymbolism exuded an eerie fusion of ancient and modern worlds.

　　"He told me the key opened a box where he kept many secrets."Langdon felt a chill to imagine what kind of secrets a man like Jacques Saunière might keep. Whatan ancient brotherhood was doing with a futuristic key, Langdon had no idea. The Priory existedfor the sole purpose of protecting a secret. A secret of incredible power. Could this key havesomething to do with it? The thought was overwhelming. "Do you know what it opens?"Sophie looked disappointed. "I was hoping you knew."Langdon remained silent as he turned the cruciform in his hand, examining it.

　　"It looks Christian," Sophie pressed.

　　Langdon was not so sure about that. The head of this key was not the traditional long-stemmedChristian cross but rather was a square cross—with four arms of equal length—which predatedChristianity by fifteen hundred years. This kind of cross carried none of the Christian connotationsof crucifixion associated with the longer-stemmed Latin Cross, originated by Romans as a torturedevice. Langdon was always surprised how few Christians who gazed upon "the crucifix" realizedtheir symbol's violent history was reflected in its very name: "cross" and "crucifix" came from theLatin verb cruciare—to torture.

　　"Sophie," he said, "all I can tell you is that equal-armed crosses like this one are consideredpeaceful crosses. Their square configurations make them impractical for use in crucifixion, andtheir balanced vertical and horizontal elements convey a natural union of male and female, makingthem symbolically consistent with Priory philosophy."She gave him a weary look. "You have no idea, do you?"Langdon frowned. "Not a clue.""Okay, we have to get off the road." Sophie checked her rearview mirror. "We need a safe place tofigure out what that key opens."Langdon thought longingly of his comfortable room at the Ritz. Obviously, that was not an option.

　　"How about my hosts at the American University of Paris?""Too obvious. Fache will check with them.""You must know people. You live here.""Fache will run my phone and e-mail records, talk to my coworkers. My contacts arecompromised, and finding a hotel is no good ............